Lens Fungus and Me

[Rodinal Addict]

Greetings Comrades!
I now have three FED lenses, that came with the two FEDs I've recently bought. I'm noticing some odd threadlike things apparently in between the glass elements on one lens, ans a roundish spot on another one. Is this the dreaded fungus that I see mentioned around? Where does fungus (in lenses) come from, can it affect images, and can I remove it?

[JohnM]

1) Almost certainly fungus.

2) Generally comes from too much moisture or humidity when the camera or lens is stored for a long period of time. (Can take years to develop).

3) In the beginning, it generally doesn't affect the image. As time goes on, you lose clarity, gain flare, etc.

4) Yes, sort of. If you catch it early, you can clean it. Some people say use vinegar, some say cold cream, some say put the camera in sunlight. I've used cold cream and it worked to kill the fungus - in one case, the camera was fine afterwards. In another, the acid from the fungus had already etched the glass badly and the camera was a loss. Honestly, try the lenses out. See what the results are - your best bet is to use the lenses for whatever their worth or replace them.

[bmattock]

Also remember - fungus is a plant-like orgranism that spreads spores. Common wisdom is to keep lenses that have active fungus colonies away from lenses that don't. Dunno if it is true, but it makes sense to me.

Best Regards,

Bill "There's a fungus among us" Mattocks

[Rodinal Addict]

So, are these lenses able to be taken apart and cleaned? Is this a job for us mere mortals, or do I need any factory training?

[bmattock]

Originally posted by Rodinal Addict
So, are these lenses able to be taken apart and cleaned? Is this a job for us mere mortals, or do I need any factory training?

Because the fungus grows between the lens elements, they must be disassembled and cleaned for proper removal. And even that may not work.

1) Some folks swear by the sunlight effect. Put the lens in a windowsill in direct sunlight for a couple of days. Should kill the fungus, and might dry it up to the extent that the damage is not as visible. I hear some folks say it works for some lenses some of the time. Your milage may vary.

2) Fungus gets in between cemented-together elements - this is bad. Lens elements used to be held together with a cement based on balsa-wood, and it is what the fungi are eating or have eaten. Therefore, chances are good that not only would you have to disassemble the lens, but also split a glued-together element to get at the fungi.

3) Fungus, once it eats, leaves an acidic residue that can and has etched glass - like a fossil in stone. Sometimes even removing the fungus will still leave a damaged lens behind. Probably no way to tell until you actually remove the fungus, either.

As mentioned on other threads here - many have tried to take apart lenses and been surprised when the aperture leaves fall out, little springs and ball bearing detents fly out, etc... Do you want to try this? Depends on the person. I've taken apart a few lenses and wrecked 'em by so doing. But they weren't much to begin with, so oh well.

There are some books on the subject - mentioned in the other thread current here on taking apart an Elmar lens. You might pick up the book and take a peek?

My general advice - most of us who are not particularly gifted mechanically don't want to do this.

Best Regards,

Bill Mattocks

[Doug]

Originally posted by bmattock
2) Fungus gets in between cemented-together elements - this is bad. Lens elements used to be held together with a cement based on balsa-wood, and it is what the fungi are eating or have eaten. Therefore, chances are good that not only would you have to disassemble the lens, but also split a glued-together element to get at the fungi.

Good info, Bill! Just an incidental comment about the cement used in years past, not related to balsa wood, which of course is that very light wood from Central/South America used in model airplanes, for instance.

Now replaced by better synthetics, the old adhesive involved Canada balsam, which is a yellow oily turpentine extracted from the balsam fir tree, also used in paints and polishes. And perhaps yummy plant food for fungi. :-)

[Laika]

Originally posted by Rodinal Addict
So, are these lenses able to be taken apart and cleaned? Is this a job for us mere mortals, or do I need any factory training?

What lens are we talking here? an Industar 26 or 61?.. I've found these very easy lenses to work on and I think you should have a go at cleaning them if you have some basic tools, what do you have to lose? Which side of the aperture blades is the fungus? ... If your interested to have a go yourself let me know and I could post some helpful stuff/pics one night next week.

[ZeissFan]

Any lens fungus should be removed. Either have the lens serviced or do the work yourself, but I most definitely would remove any spores or fungus on lens elements.